<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>01_引出生命周期</title>
    <link rel="shortcut icon" href="../../favicon.ico">
</head>
<body>
<div id="test"></div>

<!--引入react核心库-->
<script src="../js/react.development.js"></script>
<!--引入react-dom，用于支持react操作DOM-->
<script src="../js/react-dom.development.js"></script>
<!--引入babel，用于将jsx转为js-->
<script src="../js/babel.min.js"></script>

<script type="text/babel">
    // 创建组件
    class Life extends React.Component {

        state = {opacity: 1}

        death = () => {

            // 卸载组件
            ReactDOM.unmountComponentAtNode(document.getElementById('test'));
        }

        // 组件挂载完毕
        componentDidMount() {
            this.timer = setInterval(() => {
                let {opacity} = this.state;
                opacity -= 0.1;
                if (opacity < 0) opacity = 1;
                this.setState({opacity}, () => {
                })
            }, 200);
        }

        // 组件将要卸载
        componentWillUnmount() {
            // 清除定时器
            clearInterval(this.timer)
        }

        // 初始化渲染和状态更新之后
        render() {
            return (
                <div>
                    <h2 style={{opacity: this.state.opacity}}>React 学不会怎么办？</h2>
                    <button onClick={this.death}>不活了</button>
                </div>
            )
        }
    }

    ReactDOM.render(<Life/>, document.getElementById('test'));
</script>
</body>
</html>